Are you aware of this thread?
Don't let the title fool you. It is a very detailed exposition of setting up a media PC with multiple HD Homeruns running WMC.
Also, the HD Homerun Prime is a cable-card only tuner. No OTA and I believe no clear QAM.
Yes, I've been reading it, along with Assassin's beginner's guide. I'm actually thinking about making an HTPC myself, but I haven't decided on the hardware yet. The one 1hd_addict picked looks too small for any internal expansion cards.
Didn't know the Prime was CableCard-only. Are you aware of any HDHomeRun or other tuners that will tune OTA and also accept a CableCard for encrypted QAM?